Internal-combustion engine.



lit

UNITED sTA'rEs PATENT OFFICE.

LOUIS ILLMER, an, or READING, rnnNsYLvANiA, ASSIG-NOR. T0 ILLMER, GAS

' ENGINE COMPANY, A oonrona'rron or DELAWARE.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent.

Patented Mar. 3, 1914.

To'all whom it may concern Be it; known that 1, Louis TLLMER, Jr.,

citizen of the United States, residing at- Reading, in the county ofBerks and State of Pennsylvania, have invented certain new and usefulImprovements in Internal-Combustion Engines, of which the following is aspecification.

This invention relates to a simplified pumping device for charging adouble acting power cylinder of a high powered two cycle gas duct, theinner end of which communicates with the respective pump chamber a 1while the outer end communicates both with said pump chamber and itsrespective inlet valve of the power cylinder. A control valve isprovided for each end of the pump,

each of which valves alternately places itsrespective end of the pumpchamber in communication with the air supply and the inner end of itsrespective gas duct in communication with the gaseous fuel supply, andupon changing its position, closes the separate air and gas supplies andplaces the inner end of said gas duct in direct communication with thepump .chamber, thereby permitting the pump to discharge airsimultaneously through both of its communications with the gas duct,while sending forth its charge to the power cylinder. During its suctionstroke, the pump simultaneously draws air into the pump chamber and abody of gaseous fuel into the gas duct, which fuel body is confined tothe gas/duct and not allowed to become excessively diluted with air. Abody of air is maintained back of the inlet valve and within thecommunication leading to the inlet port during the entire period ofinlet closure as will hereinafter appear. Upon opening the inlet port,first a body of air is blown into the power cylinder to scavenge thesame. At this instant the pump will be on its discharge stroke, and thebody of gaseous fuel Wlll thereupon be blown out of the gas duct bymeans of a following bodyof air, but before reaching the inlet port,-thisbody of gaseous fuel will meet, and be mixed wit-h, a portion of theair simultaneously discharging from the communication between the pumpand the outer end ofthe gas duct, to form an explosive mixture body,which upon passing into the'power cylinder, takes its place therein as aworking charge. At the end of the discharge. stroke of the pump, theentire conduit system will again have been filled with air. The body ofair lying back of the inlet valve is held inthis position and thegreater portion of this air constitutes the scavenging air for the nextfollowing mixture charge. The single pump therefore draws the air andthe gaseous fuel from their respective supplies and measures, forms andlets forward into the ends of the. power cylinder, alternate bodies ofair and a mix ture of 'air and gaseous fuel, so as to scavenge the powercylinder with an air body after each explosion. This scavengingoperation is followed by the introduction of the mixture body which isfurther compressd in the power cylinder, ignited, expanded and finallyexhausted in essentially the usual manner of explosive engines.

My invention also involves the use of a large annular inlet valvesurrounding the piston rod, which inlet valve co-acts witha special lugformed inthe cylinder head wall, causing the incoming charge to maintain the characteristic formation of the bodies of air and gaseous fuelmixture with- .in the power cylinder after passing the inlet valve.

My invention further involves various other features of major or minorimportance, such as the means of control, regulation and adjustment ofthe pump devices, all of which will be fully set forth hereinafter andpointed out in the claims.

Reference is had to the accompanying drawing which illustrates thepreferred manner in which the various elements of my invention may beembodied, and which shows a vertical cross-section through the pump andthe power cylinder of a double acting two cycle gas engine.

The water jacketed power cylinder 1 is provided with a piston 2, whichis mounted on the piston rod 3, one end of whlch pro jects through thevalve housing 5 and the cylinder head 4, which latter contains thecombustion chamber 51. The piston rod 3 is attached to themain crossheadof the engine and is reciprocated by its crank mechanism in the usualmanner. The inlet valve 6 surrounds the piston rod and is slid-ablymounted in parts of the valve housing 5, while the exhaust ports 7 arelocated intermediate the cylinder ends and are adapted to be overrun bythe piston in a manner customary in this type of engine.

As far as the present invention is concerned, the drive for the inletvalves 6 may be of any suitable type, but I prefer to operate thesevalves mechanically by means of an eccentric mounted on the ma'fiishaft, which mot-ion is toggled and transmitted through the rock shaft8, the double rocker 9 and the push rod 10, which rods are attached tothe rear flanges of the inlet valves. Details of such a mechanism areset forth in my oo-pending application No. 539,218, filed Jan. 21, 1910.

WVithin the pump cylinder 11 is provided the pump piston 12, actuated bythe piston rod 14: which is attached to a separate crank mechanism (notshown) and driven in synchronism with the power piston movements, asiscustomary with such attached pumps in this type of engine. As one ofthe inlet valves 6 opens, the pump piston 12 will be approaching midposition in its discharge stroke, so that the charge will be forcedthrough the open valv'e into the ower cylinder. The pump is suppliedwith gaseous fuel through the gas supply pipe 15, which is under controlof the gas check valve 16, whence the. gas passes into the gas chamber29 to feed the gas suction ports 17.

The air supply chamber 18 communicates with the atmosphere through theperforated wall shown, or if desired the air chamber may be connectedwith the atmosphere by means of a separate pipe, not shown. In theconstruction shown the air is fed directly into the pump chambers 27 aor 27, through the air suction ports 19 and the cylinder ports 20. 7Each set of air suction ports 19 and gas suction ports 17 is controlledby one of the common pump valves 21. These two valves are mechanicallyoperated in synchronism with the pump piston motion through the rockerarms 38 which are tied together by the valve link 34. The pump valve 21alternately assumes the two extreme positions shown in the drawing. Inone of these positions (shown for the crank and valve), the air and gassupplies are shut off from the pump cylinder by closure of the gassuction port 17 and the air suction port 19, and the cylinder port 20communicates directly with the discharge port 28. In the reverseposition (shown for the head end valve) the suction ports are full openand the discharge port isclosed. These valves are preferably to bedriven by the same eccentric that operates the inlet valve, all of whichis more fully shown in my co-pending application above referred to.

The air and gas movements under control of the valves 21 will behereinafter described in detail in connection with the operation of thepump.

As stated, the system of conduits em' ployed consists of two separateducts leading from each end of the pump, one the gas duct 22 and theother the air duct 23, which Each pump valve is adapted to control oneof the discharge ports 28 simultaneously with the corresponding set ofair and gas suction ports 19 and 17 respectively. The

arrangement of the three ports, 17, 19 and 28 and the operation of thesame by means of a single valve, permits the use of a small number ofmoving parts and constitutes an important feature of my presentinvention.

The gas ducts 22 also communicate with the gas supply pipe 15 through apassage made up of the gas chamber 29, the gas suction port 17 and thegas pocket 30. A separating wall 31 is located between the airpocket 26and the gas pocket 30 the purpose of which will be hereinafter setforth.

The governor throttle valve 32 controls the gas supply and serves toregulate the engine by connecting the throttle through a suitablelinkage with the governor ofthe engine, (not shown).

Assuming the parts to be in the position shown, and that the two pistonsare moving in the direction indicated by arrows, the power piston 2 hasjust passed its head end dead center position and both the crank andexhaust ports 7 and the crank end inlet valve 6 are open. The workingcharge in the head end of the power cylinder is under maximumcompression and has just been ignited by means of the spark plug 35. Thepump piston 12 is on its downward stroke, which rarefies the air in thehead end parts of the pump, including the pump chamber 27 the air duct23 and the gas duct 22 and up to the gas suction port 17 The latter porthav ing been opened shortly after the reversal of the pump piston, abody of gaseous fuel will therefore be flowing from the gas chamber 29,through the gas pocket 30 and into the gas duct 22, as illustrated bythe lines A which indicate the flow of a gas'body.

It is intended that the ducts and the valve ports be designed to permitthe forward movement of the stratified bodies of air and of gas withoutexcessive intermingling. As the body of gas is being sucked into the gasduct 22, the air previously lying ahead of the gas will therefore bepushed forward. The gas duct has a sufliciently large capacity to holdthe'full gas charge required by the power cylinder, and, at the end ofthe suction stroke of the pumpthe fully entered body of gas may extendup to the mixing ports 24. At light loads, the governor throttle valve32 causes a smaller body of gas to be sucked into the gas duct 22 andfor this condition the gas body will not extend up to the mixing ports,and a body of air will lie between said ports and the gas body, asindicated by the letter B. As the above operations take place in the gasduct, air is being simultaneously sucked directly into the pump chamber27 through the cylinder port 20 and the air-suction port 19, asindicated by the arrows. The air described as being pushed ahead of thebody of gas entering the duct 22, also flows, through the communicatingbranch 23 toward the pump chamber 27, whereby the pump chamber is fed byboth the air and the gas suction valves but air alone enters the saidchamber; The air lying behind the closed inlet valve in the common duct25 is not displaced by the sucking action of the pump but remains inposition to be introduced into the power cylinder as scavenging airahead of the following mixture body. Upon the reversal of the pumppiston12, the pump valves 21 promptly change their positions, the headend valve closing the air and gas suction ports 19 and 17 respectivelyand opening the discharge port 28. The above described suctionoperations are then repeated in the crank end of the pump.

During the first portion of the pump discharge stroke the charge iscompressed so as to be ready to flow into the power cylinder at theinstant the inlet valve opens. At or about mid stroke of the pump, thehead end exhaust port 7 and the head end inlet valve 6 open. Prior tothis time, the head end air discharge port28 will. have partially openedand the inlet opening alone times the for ward flow of the bodies of airand of mix ture into the power cylinder. Thereupon the continued act-ionof the pump piston forces the air out of the pump chamber 27 whichcauses a body of air to be discharged from both the air duct 23 and thegas duct 22. The movement of this air forces into the power cylinder,first, the body of air lying in the common duct 25 which constitutes theinitial portion of the scavenging air. The body of air flowing out ofthe pump chamber and into the gas duct 22, passes through the dischargeport. 28 and the air pocket 26.

The air pocket permits eddying of the air after it leaves the partiallycontracted discharge port 28 and thus spreads the air over the entirearea of the air pocket 26 before it discharges into the neck 37. The gaswill then be pushed out of the gas duct 22 ina body Without excessiveintermingling with the air. At this instant, air is being dischargedsimultaneously through the air duct 23 and any air that may have beenpreviously lying in the gas duct between the gas body and the mixingports 24 will serve as scavenging air in addition to that described ashaving been blown out of the common duct 25. As the gas body reaches themixing ports 24-, it will be thoroughly mixed with the air that is beingdischarged from the air duct 23 and so forms the explosive mixture body.The last named body passes into and through the common duct 25 and flowspast the open inlet valve 6 and takes its place in the power cylinder asa working charge, The body of explosive mixture thus formed andintroduced, is followed by the remaining air still being discharged fromthe pump chamber, which body of air flows into the common duct 25,pushing forward and ahead of it, the body of explosive mixture, untilthe latter is entirely entered into the power cylinder. At the end ofthe discharge stroke of the pump, which coincides approximately with theinstant of inlet closure, air alone lies behind the inlet valve 6 in thecommon duct 25, the gas duct, and all of the other pump parts except thegas pocket 30. As the pump piston again reverses its stroke, operationssimilar to those for the head end charging just described, are broughtabout in the crank end of the pump and in the crank end of the powercylinder. The charging operation of thecrank end of the power cylinderis illustrated in the drawing in which the remaining portion of the gasbody yet to be mixed with air is indicated by the letter A and is shownfor the instant when a considerable ortion of the mixture body isalready ormed. Such mixture is indicated by the letter C, a considerableportion of which is shown as having already entered the power cylinderand as pushing ahead of it the body of scavenging air B that precededit. The mixture body extends back to the mixture ports where it isformed.

It will be seen therefore, that by means of my invention involving theuse of a single, double acting pump fitted with only two valves, Isupply the power cylinder of a double acting gas engine with alternatebodies of scavenging air and of explosive mixture, which passsuccessively into 4he power cylinder, the scavenging air cooling andcleansing the cylinder and the mixture body entering as a workingcharge; and this in turn followed by a second body of air, of

which aminor portion may be allowed to follow the mixture body into thepower cylinder while the major portion of the said air body is made tolie back of the inlet valve, isolating it from the gas supply. Theseresults are obtained by sucking air into the pum cylinder and at thesame time sucking a bOC y of aseous fuel into a duct and'subsequentlylowing the body of gas out of said duct by means of a body of air andconverting the said gas body into a mixture body by simultaneouslyblowing air into the gas body as it passes on its way toward the powercylinder.

If desired a mixture body of air and gas may be sucked into the gas duct22 instead of working with a stratified gas body, in which event themixture would be formed at anearlier period in the engine cycle and theamount of explosive mixture stored in the ducts would thereby beincreased. In such modified operation, the air discharge through the airduct 23 would have to be greatly reduced or made to cease entirely. Itmay also be pointed out that the double ducts, i. 6.: the air duct 23and the gas duct 22, leading from the pump, may separately extend up tothe inlet valve without forming the common duct 25 at all. At the end ofthe suction stroke a body of air will then lie in the gas duct ahead ofthe body of gas and the explosive mixture will be formed at the inletvalve, in which case the mixing ports 24 may be eliminated. The actionof the single pump however remains substantiallythe same as in thedesign shown in the drawing. Since the gas body begins to enter the gasduct 22 before the gas suction port 17 has fully opened, a supplementaryduct or gas pocket 30 is provided between said port and the stratifyingneck 37. The object of the gas pocket 30 is to give the gas anopportunity to eddy or whirl so as to cause the gas to spread beforedischarging from this pocket into the stratifying neck 37 As the gasbody is sucked into the gas duct 22, it will then push forward the bodyof air lying ahead of it without causing excessive intermingling. Thegas pocket 30 will at all times hold a relatively small volume of gasand during the discharge stroke of the pump this gas is trapped and heldin place until the gas suction port 17 again opens. The separating wall31 performs the additional function of a baflie and causes the gas toflow directly into the stratifying neck 37 as it discharges from theocket 30. It may be pointed out that should said gas body pick up someof the air during the process ofstratification, it will not materiallyaifect the efiiciency of the engine unless the mixture body is allowedto become excessively diluted with air, in which case it would retardthe rate of ignition. In the design of the ducts, the purpose is toeliminate pockets and the like so as to best facilitate the describedStratification. The bodies of scavenging air and of explosive mixtureare necessarily charged into the power cylinder at a rather highvelocityin order to complete this operation within the short timeallowed for the charging period when running at the usual speed for thistype of engine. To prevent a portion of the mixture body from flowincompletely through the power cylinder an out of the exhaust ports,resulting in both waste of gas and a failure to get the cylinder full ofmixture, the inlet opening should be of 'liberal dimensions and the 'maor portion of the kinetic energy attained by the charge in flowing bytheinlet valve should be absorbed before the charge has passed anyconsiderable distance into the power cylinder. I accomplish this end byhaving the inlet valve 6 surround the piston rod 3 and causing thecharge to flow in the common duct 25 which gives the charge a directionofflow parallel with the horizontal axis of the power cylinder beforereaching the annular inlet port 36. I also provide a wall or eddying lug38, surrounding the head of the inlet valve 6 and formed in the cylinderhead 4, which lug is adapted to intercept the direct flow of the chargetoward the exhaust ports and to co-act with the inlet valve in thefollowing manner As the mixture charge enters the cylinder (indicated inthe drawing by the letter C) itflows past the inlet valve, which, whenopen, acts as a baflieto spread the as mixture into a hollow cone-likeor funne shaped formation. The mixture bod thus discharged, strikes thesurrounding e dy lug 38 approximately normally to its direction of flow.Such action impedes the :fiow immediately after leaving the inlet valveand results in the creation of intense eddy currents which cause themixture to whirl and lose a considerable portion of its high initialvelocity. The resulting reduction of velocity causes the mixture body tospread and to drive out the scavenging air ahead, in a body, and permitsthe cylinder to be almost entirely filled with the mixture body. In thismanner the formation of alternate bodies of scavenging air and ofexplosive mixture may be maintained within the ower cylinder after theyhave passed the in ct valve.

In order to control the position of the mixture body as it takes itsplace within the power cylinder, I provide a pump bypass valve 39through which the pressure side is placed in direct communication withthe suction side of the pump. This by-pass may be adjusted by hand whilerunning, by means of a lever 39 with which the effective discharge ofthe pump may be varied at will. This adjustment in turn fixes the finalposition of the mixture body within the power cylinder previous to thepiston compression period. By means of the pump by-pass valve 39, theadjustment of the said succeeding body of air is under direct controland this, in connection with the limited discharge capacity of the pump,permits the use of the described alternate bodies of scavenging air andof a mixture of air and gas, without the possibility of at any timeblowing the mixture body out of the power cylinder by an excessivelylarge succeedlng air body. This feature is especially important instarting the engine or while running at variable speeds. In addition tothe above described control, the pressure side of the pump is furtherplaced in communication with the suction side by means of the timedpiston by-pass ports 40, which are overrun as the pum piston 12approaches its dead center position and at which time only the statedcommunication will be established. At this instant the inlet valve 6will have closed and the air in the gas duct 22, the air ducts 23 andthe common duct 25 will be relieved of their pressure through the pistonby-pass port 40. This obviates the necessity of providing the additionalpiston displace ment that would otherwise be required to expand toatmosphere, the air confined in the large clearance space. By means ofthe ports40 it is also possible to maintain a more uniform suctioncapacity of the pump through wide variations in the engine speed.

Each air duct 23 is provided with an air check valve 41 mounted on avalve seat 42,

"which is capable of being rotated or otherwise adjustably set, by meansof the lever 43. The valve 41 opens'inwardly toward the pump chamber, sothat when gas is being sucked into the gas duct 22, the air check valve40 opens freely. By proper adjustment and locking of the lever 43 thevalve seat 42 is so set as to allow a predetermined area of discharge.Accordingly a relatively large body of gas may at all times be suckedinto the gas duct without being perceptibly aflected by any throttlingadjustment made for the air discharge through the duct 23. As the airduct discharge is restricted, a larger portion of the pump chamberdischarge can be made to pass through the gas duct 23. Thus, if desired,the gas may be blown out of the duct 22 more or less rapidly, while theair discharged through the duct 23 will becorrespondingly reduced inamount. The adjustment of the valve seat 42 therefore permits avariation in the ratio of air to gas in the formation of the mixturebody to meet variations in the calorific value of the gaseous fuel. Atthe same time that the valve seat 42 is made to throttle the air ductdischarge, it is expedient to correspondingly open the setting of theby-pass valve 39 so as not to shift the mixture body into the powercylinder. If preferred, a properly timed mechanically operated valve maybe substituted for the automatic check valve 41.

Another mode of changing the ratio of air to gas, which however does notrequire the adjustment of the valve 39, is shown in the drawing. Thepipe 44 supplies atmospheric air or other diluting gaseous fluids to theport 45 (shown dotted) located in the cover plate of the pump valve 21.This valveis made up of a body portion, cast hollow, and is providedwith end walls closing this hollow space. One of said walls carries aport 46, which registers with a port 45 during the suction period of thepump. Communication is established between the hollow portion of thevalve body and the gas suction port 17 through a series of small holes47, so that diluting air may be sucked through the hollow body of thevalve 21 and mixed with the gas supply at the time that the latter isentering the gas pocket 30. During the discharge stroke of the pump, theport45 is not allowed to register with the port 46. By adjusting thediluting valves 48 the ratio of air to gas in the mixture body formed atthe mixing ports 24 may be varied at will.

For the purpose of balancing or otherwise independently adjusting therelative amount of mixture body charged into either end of the powercylinder, 1 provide separate air throttle valves 49 for each of the airsuction ports 19. These valves may be adjusted from the outside whilerunning, by any convenient means, not shown. It will be seen that thethrottling of either of the air suction ports 19 will indirectly cause arelatively large portion of gas to be sucked through the correspondinggas suction port 17 and in this manner the mean effective pressure inone end of the power cylinder may be changed with respect to the other.

The gas supply pipe 15 is provided with an automatic gas check valve 16,which may be placed in any convenient part of the gas supply line. Thevalve 16 prevent-s flooding thegas ducts and the pump chamber with gaswhen starting the engine, which starting may be done, as usual, withcompressed air. The valve 16 is comparatively light in construction,though sufliciently heavy to prevent the gas pressure alone from liftingthe valve perce tibly, but the additional rarefaction produced whenstarting the pump, allows the proper amount of gas to pass into the duct22 without however sucking gas into the pump chamber.

The particular construction illustrated is subject to variousmodifications without departing from the spirit of or narrowing thescope of the present invention, for instance, the gas suction port 17may be located to feed the duct 22 at any point between the mixing port24 and the pump chamber, and, by the use of proper check valve orvalves,

III

the gas may be prevented from sucking directly into the pump chamber,thus accomplishing the same results. Also, the air suction port 19 maybe made to feed into any part of the duct 23, and furthermore thedischarge valve may be eliminated by suitably rearranging the point ofadmission of the gas into the gas duct.

What I claim is 1. In an internal combustion engine of the scavengingtype having a power. cylinder with controlled inlet and exhaust ports, acharging pump comprisin a single cylin der and a piston, a gas iuct oneend of which communicates with the pump and the other end with both theump and the power cylinder, separate supp ies of air and gas eous fuel,means for admitting air to the pump and a body of gaseous fuel into thegas duct, the pump during its compression stroke serving to blow saidgaseous fuel body out of thegas duct and into the power cylinder bymeans of a body of air, a portion of which body of air is held back ofthe inlet valve during the entire period of inlet closure.

2. In an internal combustion engine of the scavenging type having apower cylinder with controlled inlet and exhaust ports,-

a charging pump comprising a single cylinder and a piston, a gas ductone end of which communicates with the pump and the other end with boththe pump and the ower cylinder,lseparate supplies of air an gaseousfuel, means admitting air to the pump and a body of gaseous fuel to thegas duct, said pump during its compression stroke discharging airthrough both of its communications with the duct to blow said gaseousfuel body out of the-duct and mix it with air and to enter the mixturebody thus formed into the power cylinder, and means for controlling theratio of air to gas in said mixture body.

3. In an internal combustion engine of the scavenging type, having apower cylinder with controlled inlet and exhaust ports, a charging pumpcomprising a single cylinder and a piston, a gas duct and an air duct,each establishing communication with the pump and a commonduct-discharging to the inlet port, separate supplies of air and gaseousfuel, means for admitting air to the pumpand a body'of gaseous fuel'intothe gas not, said pump during its compression stroke dischar g airthrough both the air andv the gas dil cits simultaneously to blow saidgaseous fuel body out of the gas duct and means converting said air andgas into an explosive mixture body prior to entering the same into thepower cylinder.

4. In an internal combustion engine of the scavenging type having apower cylinder with controlled inletand exhaust ports, a charging pumpcomprising a single cylinder andv a piston, a gas duct one end of whichcommunicates with the pump and the other end with both the pump and thepower cylinder, separate supplies of air and gas eous fuel, a valveadmitting air to the pump cylinder and a body of gaseousfuel into thegas duct and commanding one of the communications between the pump andthe duct, the pump during its compression stroke discharging air throughboth of its communications with the duct to blow said gaseous fuel bodyout of the duct and mix it with air and to enter the explosive mixturethus formed, into the power cylinder, by means of a body of air, aportion of which body of air is held back of the inlet valve during theentire period of inlet closure.

5. In an internal combustion engine of the scavengingtype having a powercylin-. der with controlled inlet and exhaust ports, a charging pumpcomprising a single cylinder and a piston, a gas duct of which its innerend communicates with the pum and its outer end communicates with both epump and the power cylinder, an air and a aseous fuel supply means, avalve arranged alter nately'to place the pump cylinder in communicationwith the air supply to admit air and to place the inner end of the gasduct in communication with the gas supply to admit a body of gaseousfuel, and upon changing its position, to close the air and gas suppliesand place the inner end of the gas duct in direct communication with thepump cylinder toiblow said body of gaseous fugl out of the duct and intothe power cylin er.

6. In an internal combustion engine of pump and a body of gaseous fue tothe duct,

the pump during its discharge stroke serving to blow the body of gaseousfuel out of the duct and mix it with air and to send forth into thepower cylinder, first a body of scavenging air, then a mixture body ofair and gaseous fuel and then a second body of air, and means adjustablycontrolling the amount of air that is allowed to follow the mixture bodyinto the power cylinder prior to inlet closure. F

7. In an internal combustion engine of the scavenging type, having apower cylinder with controlled inlet and exhaust ports, control meansincluding an air measuring device of predetermined volumetric capacityby which bodies of air and of explosive mixture are measured and sentforward alternately into the power cylinder, the movements of saidbodies being so timed that upon opening of the inlet and exhaust ports,a body of air will first be blown into the powercylinder to scavenge thesame, then a mixture body of air and fuel, followed, prior to inletclosure-by a second body of air discharged from and limited by-thepredetermined volume of said measuring device, a portion of said secondbody of air being held back of the inlet valve during the entire periodof inlet closure.

8. In an internal combustion engine having a power cylinder withcontrolled inlet and exhaust ports, a pump comprising a single cylinderand a piston for charging alternate bodies of scavenging air andexplosive mixture into the power cylinder, separate supplies of air andgaseous fuel, a gas duct one end of which communicates with the pump andthe other end with both the pump and the power cylinder, means admittingair into the pump, and means, including a gas pocket, for admittinggaseous fuel into the gas duct, in'the manner and for the purpose setforth.

9. In'an internal combustion engine having a power cylinder withcontrolled inlet and exhaust ports, a pump comprising a single cylinderand a piston for charging alternate bodies of scavenging air andexplosive mixture into the power cylinder, separate supplies of air andgaseous fuel, a gas duct one end of which communicates with the pump andthe other end with both the pump and the power cylinder, means foradmitting air into the pump and a body of gaseous fuel into the gasduct, and an automatic check valve controlling the gas supply for thepurpose set forth;

inder and a piston, a gas duct one end of which communicates with the.pump and the other end with both the pump and the power cylinder,separate supplies of air and gaseous fuel, means for admitting air tothe pump and a body of gaseous fuel to the duct, the pump during itsdischarge stroke serv ing to blow the body of gaseous fuel out of theduct and into the power cylinder by means of a body of air, and a bypassmeans in the pump for relieving the pressure in the duct as the pumppiston approaches the end of its discharge stroke.

11. In an internal combustion engine having a power cylinder withcontrolled inlet and exhaust ports, a pump comprising a single cylinderand a piston for charging alternate bodies of scavenging airand-explosive mixture into the power cylinder, separate supplies of airand gaseous fuel, a gas duct one end of which communicates with the pumpand the other end with both the pump and the power cylinder, means foradmittin air into. the pump and a body of gaseous uel into the gas duct,and an adjustable throttle means, in the air supply to the pump, forregulating the suction influence of the pump while in action.

In, testimony whereof I affix my signature in presence of two witnesses.

LOUIS ILLMER, JR.

